ABSTRACT:

The construction of Flaming Gorge Dam in 1964 caused significant changes to the channel form and juvenile fish habitat. To mitigate for degraded habitat, spring high flow dam operations were changed to improve juvenile off-channel habitat for razorback sucker. In this study, we evaluated whether these environmental spring flow releases can be met with future hydrology that incorporates climate change. We found that the model performed poorly in years with an average spring runoff and well in dry, moderately dry, and wet years regardless of whether climate change was considered. Next, we sought to increase the reliability of meeting environmental flow recommendations by adjusting the threshold values that define the hydrologic classification for each year and days at power plant capacity. We found that changing the threshold for each hydrologic classification was more sensitive than changing days at power plant capacity and that only by making extreme alterations of those values could we get significant improvement in the reliability of meeting environmental flow objectives.

ABSTRACT:

The dataset contains a digital elevation model (DEM) derived from a 2011 LiDAR survey of the Yampa River collected by the Utah State University LASSI Service Center. The DEM only contains the Yampa River in Deerlodge Park within Dinosaur National Monument, Colorado. LiDAR data was collected within Yampa Canyon but is not included in this release. Contact the Center for Colorado River Studies at Utah State University for the entire LiDAR dataset.

ABSTRACT:

Morphodynamic model research code for sand bed rivers used in Leonard and Wilcock (in Review). Morphodynamic models evolve the bed surface grain size and topography from initial conditions to a steady state using conservation of mass and momentum for open channel flow and sediment mass conservation. We use a simplified version of channel geometry with constant width and no floodplain such that the only adjustment is in bed texture and bed aggradation or degradation. The model starts with a specified slope and bed grain size at each model node and calculates bed shear stress from a specified discharge to predict the transport rate and grain size. Bed topography and grain size adjust based on the difference between the mass of each sediment size fraction delivered to and transported from each node at each timestep. The 1D shallow water equation of mass and momentum conservation describes flow within the rectangular channel. Flow resistance and the skin friction portion of the total boundary stress are specified using the Wright and Parker (2004b) formulation, which accounts for the effects of density stratification and flow resistance over dunes. The grain-size-specific formulation of the Exner equation (Parker et al., 2007), which conserves sediment mass for individual size fractions, determines bed grain size and topography. The channel bed is divided into an upper active layer that exchanges with the bed material load, a lower substrate layer that maintains a constant grain size, and an interface layer that exchanges sediment between the active layer and the substrate as the bed aggrades and degrades (Hirano, 1971). The active layer thickness is specified as the height of the bedforms, predicted as a function of flow depth using the relation of Julien and Klaassen (1995). The grain size of the interface layer evolves as the bed aggrades and erodes using the relation formulated by Hoey and Ferguson (1994) and Toro-Escobar et al. (1996). Grain-size specific volumetric bed material transport rates are calculated using a separate transport relation for bed and suspended loads. Total volumetric bed material transport is the sum of transport of each grain size fraction in the bed and suspended loads. We use the Wright and Parker (2004b) entrainment model (W-P) coupled with a Rouse profile and van Rijn (1984) initiation of suspension criterion to estimate suspended load transport. W-P is a modified version of the Garcia and Parker (1991) (G-P) entrainment model that accounts for reduced mixing due to density stratification in the presence of large suspended loads. G-P and W-P are the only entrainment models with a mixed-size hiding function tested against field data, making this relation ideal for predicting size-selective transport in the suspended load that drives the sorting of bed grain. Bed load is calculated from the Ashida and Michiue (1972) relation (A-M), which includes the Egiazaroff (1965) hiding function. A-M was developed from flume measurements of sand bedload, making this relation ideal for our modeling purpose.

ABSTRACT:

The dataset contains a digital elevation model (DEM) derived from a 2011 LiDAR survey of the Yampa River collected by the Utah State University LASSI Service Center. The DEM only contains the Yampa River in Deerlodge Park within Dinosaur National Monument, Colorado. LiDAR data was collected within Yampa Canyon but is not included in this release. Contact the Center for Colorado River Studies at Utah State University for the entire LiDAR dataset. This data release also includes the shapefile for the delineated channel boundaries in 2013 and 2019 and tables S2 and S3 in Leonard et al. (2023).

ABSTRACT:

The dataset contains a digital elevation model (DEM) derived from a 2011 LiDAR survey of the Yampa River collected by the Utah State University LASSI Service Center. The DEM only contains the Yampa River in Deerlodge Park within Dinosaur National Monument, Colorado. LiDAR data was collected within Yampa Canyon but is not included in this release. Contact the Center for Colorado River Studies at Utah State University for the entire LiDAR dataset. This data release also includes the shapefile for the delineated channel boundaries in 2013 and 2019 in the folder titled "channelBoundaries" and tables S2 and S3 in Leonard et al. (2024). The gibb.m file contains a Matlab function to preform the two-parameter Gaussian likelihood Bayesian model used in Leonard et al. (2024).

ABSTRACT:

Morphodynamic model research code for sand bed rivers used in Leonard and Wilcock (in Review). Morphodynamic models evolve the bed surface grain size and topography from initial conditions to a steady state using conservation of mass and momentum for open channel flow and sediment mass conservation. We use a simplified version of channel geometry with constant width and no floodplain such that the only adjustment is in bed texture and bed aggradation or degradation. The model starts with a specified slope and bed grain size at each model node and calculates bed shear stress from a specified discharge to predict the transport rate and grain size. Bed topography and grain size adjust based on the difference between the mass of each sediment size fraction delivered to and transported from each node at each timestep. The 1D shallow water equation of mass and momentum conservation describes flow within the rectangular channel. Flow resistance and the skin friction portion of the total boundary stress are specified using the Wright and Parker (2004b) formulation, which accounts for the effects of density stratification and flow resistance over dunes. The grain-size-specific formulation of the Exner equation (Parker et al., 2007), which conserves sediment mass for individual size fractions, determines bed grain size and topography. The channel bed is divided into an upper active layer that exchanges with the bed material load, a lower substrate layer that maintains a constant grain size, and an interface layer that exchanges sediment between the active layer and the substrate as the bed aggrades and degrades (Hirano, 1971). The active layer thickness is specified as the height of the bedforms, predicted as a function of flow depth using the relation of Julien and Klaassen (1995). The grain size of the interface layer evolves as the bed aggrades and erodes using the relation formulated by Hoey and Ferguson (1994) and Toro-Escobar et al. (1996). Grain-size specific volumetric bed material transport rates are calculated using a separate transport relation for bed and suspended loads. Total volumetric bed material transport is the sum of transport of each grain size fraction in the bed and suspended loads. We use the Wright and Parker (2004b) entrainment model (W-P) coupled with a Rouse profile and van Rijn (1984) initiation of suspension criterion to estimate suspended load transport. W-P is a modified version of the Garcia and Parker (1991) (G-P) entrainment model that accounts for reduced mixing due to density stratification in the presence of large suspended loads. G-P and W-P are the only entrainment models with a mixed-size hiding function tested against field data, making this relation ideal for predicting size-selective transport in the suspended load that drives the sorting of bed grain. Bed load is calculated from the Ashida and Michiue (1972) relation (A-M), which includes the Egiazaroff (1965) hiding function. A-M was developed from flume measurements of sand bedload, making this relation ideal for our modeling purpose.

ABSTRACT:

Morphodynamic model research code for sand bed rivers used in Leonard and Wilcock (2024). Morphodynamic models evolve the bed surface grain size and topography from initial conditions to a steady state using conservation of mass and momentum for open channel flow and sediment mass conservation. We use a simplified version of channel geometry with constant width and no floodplain such that the only adjustment is in bed texture and bed aggradation or degradation. The model starts with a specified slope and bed grain size at each model node and calculates bed shear stress from a specified discharge to predict the transport rate and grain size. Bed topography and grain size adjust based on the difference between the mass of each sediment size fraction delivered to and transported from each node at each timestep. The 1D shallow water equation of mass and momentum conservation describes flow within the rectangular channel. Flow resistance and the skin friction portion of the total boundary stress are specified using the Wright and Parker (2004b) formulation, which accounts for the effects of density stratification and flow resistance over dunes. The grain-size-specific formulation of the Exner equation (Parker et al., 2007), which conserves sediment mass for individual size fractions, determines bed grain size and topography. The channel bed is divided into an upper active layer that exchanges with the bed material load, a lower substrate layer that maintains a constant grain size, and an interface layer that exchanges sediment between the active layer and the substrate as the bed aggrades and degrades (Hirano, 1971). The active layer thickness is specified as the height of the bedforms, predicted as a function of flow depth using the relation of Julien and Klaassen (1995). The grain size of the interface layer evolves as the bed aggrades and erodes using the relation formulated by Hoey and Ferguson (1994) and Toro-Escobar et al. (1996). Grain-size specific volumetric bed material transport rates are calculated using a separate transport relation for bed and suspended loads. Total volumetric bed material transport is the sum of transport of each grain size fraction in the bed and suspended loads. We use the Wright and Parker (2004b) entrainment model (W-P) coupled with a Rouse profile and van Rijn (1984) initiation of suspension criterion to estimate suspended load transport. W-P is a modified version of the Garcia and Parker (1991) (G-P) entrainment model that accounts for reduced mixing due to density stratification in the presence of large suspended loads. G-P and W-P are the only entrainment models with a mixed-size hiding function tested against field data, making this relation ideal for predicting size-selective transport in the suspended load that drives the sorting of bed grain. Bed load is calculated from the Ashida and Michiue (1972) relation (A-M), which includes the Egiazaroff (1965) hiding function. A-M was developed from flume measurements of sand bedload, making this relation ideal for our modeling purpose.